Snowberry
Symphoricarpos albus laevigatus
Honeysuckle family (Caprifoliaceae)
Description:
This variety of Snowberry (Symphoricarpos albus laevigatus)
is a multistemmed shrub; it is 1¼–5' tall, similarly across, and
irregularly
branched. On older shrubs, the bark of lower branches are gray and
shredded.
otherwise they are brown and shredded. Young woody branches are brown
and smooth,
while twigs are reddish brown and smooth. Young growing shoots are
light green or light tan, terete, hollow, and glabrous to slightly
short-pubescent.
Pairs of opposite deciduous leaves occur along the twigs and young
shoots. These leaves are ¾–2½" long and ½–2" across; they are usually
oval or ovate in shape (less often obovate) and their margins are
usually smooth or slightly undulate (leaves of very young shrubs are
sometimes more
undulate). The upper leaf surface is bluish green and hairless, while
the lower leaf surface is light green to nearly white and hairless. The
petioles of the leaves are very short (up to ¼" in length), light
green, and hairless to slightly short-pubescent.
Short clusters or
elongated racemes of flowers are produced from the axils of the leaves
and terminal shoots. Including both the corolla and inferior ovary,
each flower is about 1/3" (8 mm.) long and 1/4" (6 mm.) across,
consisting of a light pink or whitish pink bell-shaped corolla with 5
lobes, a shallow light green calyx with 5 shallow teeth, a light
green ovary that is hairless and
sometimes glaucous, 5 inserted stamens, and an inserted style. The
corolla lobes extend to about one-third of its length;
these lobes are ovate in shape and ascending. The calyx is light green
and hairless.
The inferior ovary is ovoid in shape, but somewhat constricted at the
base of the calyx. The light green pedicels of the flowers are very
short (less than 1/8" or 1–2 mm. long), while other stalks of the
inflorescence are light green to reddish purple. The blooming period
typically occurs
from early to mid-summer for about 1½ months, although it may become
extended into autumn under favorable conditions.
Fertile flowers
are replaced by drupes. At maturity, these drupes are 1/3–2/3" (8–16
mm.) across, bright white, globoid in shape, and hairless. Each drupe
has a waxy-fleshy interior with a bitter flavor and a pair of nutlets.
The nutlets are 4-5 mm. long, bony white, broadly ellipsoid, and
slightly flattened
in shape. The root system is branching and woody. This
shrub can reproduce asexually when its lower stems take root after they
contact moist ground (layering).
Cultivation:
The preference is
full sun to light shade, mesic to dry conditions, and rocky, clay,
or loamy soil. This shrub is not difficult to cultivate in gardens,
although it has a tendency to become lanky with age. Winter hardiness
extends to Zone 4.
Range
& Habitat: This variety of Snowberry (Symphoricarpos
albus) is found
in the northern half of Illinois, where it is widely
scattered and uncommon (see Distribution
Map). Most shrubs in the wild have escaped from
ornamental gardens and other managed landscapes; these escaped shrubs
are the hairless (or nearly hairless) variety of this shrub,
Symphoricarpos albus laevigatus. This variety of
Snowberry was
introduced to Illinois from the Pacific Northwest. Wild shrubs of this
variety are typically found in disturbed areas, such as roadside
embankments, railroads, and rocky waste areas. The typical variety of
Snowberry, Symphoricarpos albus albus, is native to
Illinois in only
two counties (LaSalle and Kane counties), where it is rare and
state-listed as 'endangered.' The native populations of this shrub are
found in higher quality habitats, consisting of sandstone bluffs along
a river and slopes of a wooded dolomite ravine along a stream.
Faunal
Associations: Floral visitors include the
Ruby-throated Hummingbird, honeybees, bumblebees, large carpenter bees
(Xenocopa virginica), leaf-cutting bees (Megachile
spp.), mason bees
(Osmia spp.), green metallic bees (Agapostemon
spp.), Andrenid bees,
Vespid wasps, Syrphid flies, Tachinid flies, miscellaneous butterflies,
and Noctuid moths. Among these floral visitors, bees are the most
important pollinators. These floral visitors obtain primarily nectar
from the
flowers, although some of the bees may collect pollen and some of the
flies may feed on pollen. Other insects feed destructively on the
leaves and other parts of Snowberry (Symphoricarpos albus).
These
insect feeders include the larvae of leaf-mining flies (Phytomyza
albiceps, Paraphytomyza luteoscutellata),
an aphid (Aphthargelia
symphoricarpi), larvae of the Sulfur Moth (Hesperumia
sulphuraria) and
White Spring Moth (Lomographa vestaliata), larvae of
Sphinx moths
(Sphinx vashti, Hemaris diffinis
& Hemaris thysbe), and larvae of small
leaf-miner moths (Phyllonorycter mariaeella, Phyllonorycter
symphoricarpaeella); see Needham et al., 1928; Spencer
& Steyskal,
1986; Robinson & Bradley, 1965; Covell (1984/2005); and the
Microleps website (2010).
Some vertebrate animals use this shrub as a
source of food and/or cover. For example, its white drupes are eaten by
the Ruffed Grouse, Ring-necked Pheasant, Greater Prairie Chicken,
Bobwhite Quail, American Robin, Cedar Waxwing, Hermit Thrush,
Swainson's Thrush, Evening Grosbeak, and Pine Grosbeak (DeGraaf, 2002).
The drupes are also eaten by the Black Bear, while White-tailed Deer
and Elk browse occasionally on the twigs and leaves (Martin et al.,
1951/1961). Vertebrate animals that eat the drupes spread the seeds of
this shrub to new areas.
Photographic
Location: A large concrete plant container in
downtown Urbana, Illinois. The photographed shrub is Symphoricarpos
albus laevigatus.
Comments:
The variety of Snowberry that is described here, Symphoricarpos
albus
laevigatus, is not native to Illinois. However, native
populations of
the typical variety of this shrub, Symphoricarpos albus albus,
have
been found in 2 counties within the state. The native variety of
Snowberry in Illinois differs from the typical garden variety of
Snowberry as follows: 1) the native variety in Illinois is a smaller
and more compact shrub, typically only ¾–2' tall, 2) its leaves tend to
be a little smaller in size and they are more likely to have
undulate-crenate margins, 3) its leaf undersides are
pubescent, especially along the veins, rather than hairless, 4) its
fruits are only 6-8 mm. across, while the typical garden variety of
Snowberry has fruits that are 8-16 mm. across, and 5) the autumnal
color of the leaves of the native variety is more showy (usually yellow
and orange), while the typical garden variety of Snowberry has brownish
green leaves during the autumn (Young, 1991). Another shrub that is
similar in appearance to Snowberry is Wolfberry (Symphoricarpos
occidentalis). Wolfberry can be distinguished by its slightly
larger
leaves (up to 3½" long), sessile flowers and fruits, more deeply lobed
flowers (extending to about one-half of the length of the corolla), and
slightly exserted style and stamens. Wolfberry is considered an
uncommon native shrub in Illinois, although it is probably adventive at
some sites. Wolfberry is typically found in dry sunny
places, such as areas along railroads and upland prairies.